Antibacterial PVC plate and preparation method thereof

Abstract

This invention discloses an antibacterial PVC sheet and its preparation method, belonging to the technical field of PVC sheet technology. The antibacterial PVC sheet of this invention comprises the following raw materials: polyvinyl chloride resin, a composite antibacterial agent, a toughening modifier, a stabilizer, a lubricant, a processing aid, and a filler. The composite antibacterial agent is a core-shell structure particle surface-modified with a silane coupling agent. Its core is nano-cuprous oxide (Cu2O), and its outer shell is mesoporous silica (mSiO2). The mesoporous silica channels are loaded with a natural antibacterial agent—chitosan quaternary ammonium salt. This invention achieves a gradient slow release of antibacterial components, synergistic effects of three antibacterial mechanisms, and good compatibility between the antibacterial particles and the PVC matrix through a three-layer core-shell structure design: "nano-Cu2O core → mesoporous SiO2 shell loaded with chitosan quaternary ammonium salt → KH-550 surface modification." Ultimately, the prepared antibacterial PVC sheet possesses comprehensive advantages including long-lasting antibacterial effect, efficient sterilization, and excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of PVC sheet technology, specifically relating to an antibacterial PVC sheet and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) sheets possess numerous advantages, including lightweight, weather resistance, corrosion resistance, excellent formability, and high cost-effectiveness, making them widely used in architectural decoration, public facilities, home kitchens and bathrooms, and industrial protection. However, pure PVC resin itself lacks antibacterial properties. During long-term use, especially in humid, enclosed, and densely populated environments, harmful bacteria and microorganisms such as E. coli can easily adhere to and proliferate on the surface of the sheets. This not only easily leads to mold, staining, and aging failure of the sheet surface, shortening its lifespan, but also poses hygiene and safety hazards, making it difficult to meet the high standards required for use in medical and health settings, clean spaces, and high-end home decoration.

[0003] To address the lack of antibacterial properties in PVC sheets, existing technologies typically employ the doping of single organic or inorganic antibacterial agents to impart antibacterial properties. Organic antibacterial agents offer rapid sterilization and excellent initial antibacterial effects, but they generally suffer from poor thermal stability, easily decomposing and failing during high-temperature PVC extrusion and calendering processes. Furthermore, the antibacterial components are prone to migration and loss, resulting in weak long-term antibacterial performance and a significant decrease in antibacterial efficacy over extended use. Inorganic antibacterial agents offer good thermal stability and strong antibacterial persistence, but they suffer from slow sterilization rates and limited antibacterial spectrum. Conventional inorganic nanoparticles are also prone to aggregation, exhibiting poor compatibility with the hydrophobic PVC matrix. This not only leads to uneven dispersion of antibacterial components and insufficient antibacterial stability but also damages the original internal structure of the PVC sheet, significantly reducing its tensile and impact resistance mechanical properties.

[0004] Currently, some existing technologies attempt to use simple combinations of organic and inorganic antibacterial agents, but this is merely a physical mixing method and cannot achieve the synergistic effect of the two antibacterial components, making it difficult to simultaneously meet the dual requirements of rapid sterilization and long-lasting antibacterial action. Furthermore, simple antibacterial systems cannot avoid the negative impact of inorganic antibacterial components on the thermal stability of the PVC matrix, nor can they effectively protect the organic antibacterial components. During processing, the antibacterial components are severely depleted, and the problem of particle aggregation remains unresolved. The resulting PVC sheets generally suffer from poor antibacterial durability, insufficient performance uniformity, deteriorated mechanical properties, and poor processing stability, severely restricting the large-scale production and high-end application of antibacterial PVC sheets.

[0005] To address the shortcomings of existing antibacterial PVC sheets, such as a single antibacterial mechanism, inability to balance fast and slow antibacterial effects, easy aggregation and loss of antibacterial agents, poor processing stability, and difficulty in synergistically achieving both mechanical and antibacterial properties, this invention proposes a novel core-shell structured composite antibacterial agent and antibacterial PVC sheet preparation technology. Through structural optimization and surface modification design, it effectively solves many defects of existing technologies, and prepares antibacterial PVC sheets that combine broad-spectrum and efficient bactericidal activity, long-lasting antibacterial effect, excellent mechanical properties, and good processing stability. Summary of the Invention

[0006] The purpose of this invention is to provide an antibacterial PVC sheet and its preparation method. The prepared PVC sheet effectively inhibits bacteria and has excellent mechanical properties.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows: An antibacterial PVC sheet comprises the following raw materials in parts by weight: 100-120 parts of polyvinyl chloride resin, 3-15 parts of composite antibacterial agent, 3-15 parts of toughening modifier, 2-5 parts of stabilizer, 0.5-2 parts of lubricant, 1-8 parts of processing aid, and 10-20 parts of filler.

[0008] Furthermore, the preparation steps of the composite antibacterial agent are as follows: (1) Preparation of nano-Cu2O@mSiO2 core-shell particles: Weigh 5g of nano-cuprous oxide and add it to a three-necked flask containing 200mL of anhydrous ethanol and 50mL of deionized water. Disperse it by ultrasonication for 30 minutes to obtain a uniform suspension. Add 1g of CTAB and 2mL of 25% ammonia water to the suspension and stir at 400rpm and 40℃ for 30 minutes. Add 5mL of LTEOS dropwise using a constant pressure dropping funnel and continue stirring at 40℃ for 6 hours. After the reaction is completed, centrifuge at 8000rpm for 10 minutes, discard the supernatant, and wash the precipitate twice with anhydrous ethanol and deionized water. Place the washed precipitate in a vacuum drying oven at 60℃ and dry for 12 hours. Transfer it to a muffle furnace and heat it to 500℃ at a heating rate of 2℃ / min. Keep it at that temperature for 4 hours and cool it naturally to room temperature to obtain Cu2O@mSiO2 core-shell particles. (2) Chitosan quaternary ammonium salt loaded in mesoporous channels: Weigh 1g of chitosan quaternary ammonium salt, dissolve it in 100mL of deionized water, stir to dissolve, and prepare a 1wt% chitosan quaternary ammonium salt solution; add 5g of the prepared Cu2O@mSiO2 core-shell particles to the chitosan quaternary ammonium salt solution prepared above, place it in a vacuum drying oven, keep it for 30 minutes, then release the vacuum, and cycle the vacuum-decompression twice. Centrifuge the above impregnated mixture at 6000rpm for 10 minutes, collect the precipitate, wash the precipitate once with deionized water, centrifuge again, and place the precipitate in a vacuum drying oven at 50℃ for 24h to obtain composite particles; (3) Surface modification of silane coupling agent: 1g KH-550 was added to a flask containing 100ml anhydrous ethanol and 5ml deionized water, the pH was adjusted to 4-5, and the mixture was stirred to dissolve and obtain a modified solution; the composite particles prepared in step 2 were weighed and added to the above modified solution, ultrasonically dispersed for 5 minutes, and then magnetically stirred and refluxed in a 60℃ water bath for 4 hours. The mixture was centrifuged at 8000rpm for 8 minutes, the precipitate was washed twice with anhydrous ethanol, and then dried in a 60℃ vacuum drying oven for 12 hours. The dried product was then passed through a 200-mesh sieve to obtain a composite antibacterial agent.

[0009] Furthermore, the chitosan quaternary ammonium salt is hydroxypropyltrimethylammonium chloride chitosan.

[0010] Furthermore, TEOS is tetraethyl orthosilicate, CTAB is hexadecyltrimethylammonium bromide, and KH-550 is γ-aminopropyltriethoxysilane.

[0011] Furthermore, the toughening modifier is one of chlorinated polyethylene, acrylonitrile-butadiene-styrene copolymer, and methyl methacrylate-butadiene-styrene copolymer.

[0012] Furthermore, the stabilizer is a calcium-zinc composite stabilizer.

[0013] Furthermore, the lubricant is one of stearic acid, polyethylene wax, and paraffin wax.

[0014] Furthermore, the processing aid is a mixture of methyl methacrylate and butyl acrylate in a mass ratio of 7:3.

[0015] Furthermore, the filler is light calcium carbonate.

[0016] A method for preparing antibacterial PVC sheets includes the following steps: Weighing polyvinyl chloride resin, composite antibacterial agent, toughening modifier, stabilizer, lubricant, processing aid, and filler by weight; adding all weighed raw materials into a high-speed mixer and mixing at 300-500 rpm for 2-3 minutes; increasing the speed to 1000-1500 rpm and mixing for 5-10 minutes; discharging the material into a cold mixer and cooling it to 40-50℃ during mixing to obtain a dry mixture; feeding the cooled dry mixture into a conical twin-screw extruder, where it undergoes melt plasticization and technical sizing to obtain a sheet blank; passing the extruded sheet blank sequentially through a sizing table and a cooling water tank for cooling and sizing, and then traction by a traction machine to cut it to the required length to obtain the antibacterial PVC sheet.

[0017] Furthermore, the temperatures of each section of the extruder are set as follows: Zone 1 of the barrel is 160-170℃, Zone 2 is 170-180℃, Zone 3 is 175-185℃, the confluence core is 170-175℃, the die temperature is 180-195℃, and the screw speed is 15-30 rpm.

[0018] All raw materials used in this invention are commercially available.

[0019] This invention innovatively adds a compound antibacterial agent, which effectively achieves the following effects: Inorganic / organic composite antibacterial agent: Nano-cuprous oxide can slowly release copper ions, disrupting bacterial cell membranes and interfering with enzyme systems, providing a long-lasting antibacterial effect; simultaneously, chitosan quaternary ammonium salt loaded within the mesoporous silica channels adsorbs negatively charged bacterial surfaces through its positive charge, causing leakage of cell contents and achieving rapid sterilization. The synergistic effect of these two components achieves a dual effect of "rapid sterilization + long-lasting antibacterial action."

[0020] Slow-release and protective effects: The mesoporous silica shell, acting as a "nanocontainer," not only effectively protects the internal nano-cuprous oxide, preventing it from directly contacting the PVC matrix and undergoing catalytic degradation, but also controls the slow release of chitosan quaternary ammonium salt and copper ions through physical confinement, greatly extending the effective antibacterial time.

[0021] Excellent dispersibility and compatibility: By surface modification with silane coupling agent (KH-550), organic functional groups are introduced into the surface of composite antibacterial particles, which significantly enhances their interfacial compatibility with hydrophobic PVC resin, solves the problem of easy aggregation of inorganic nanoparticles, and ensures that the antibacterial agent is evenly distributed in the board, thereby obtaining stable and uniform antibacterial performance.

[0022] Processing stability: The mesoporous silica shell isolates the organic antibacterial components (chitosan quaternary ammonium salt) from the high-temperature PVC melt, preventing their thermal decomposition during processing. Simultaneously, the shell also prevents the negative impact of copper ions on the thermal stability of PVC, allowing the sheets of this invention to be stably produced using conventional extrusion and calendering processes.

[0023] Beneficial effects This invention achieves gradient slow release of antibacterial components, synergistic effect of three antibacterial mechanisms, and good compatibility between antibacterial particles and PVC matrix through a three-layer core-shell structure design of "nano-Cu2O core → mesoporous SiO2 shell loaded with chitosan quaternary ammonium salt → KH-550 surface modification". Ultimately, the prepared antibacterial PVC board has comprehensive advantages of long-lasting antibacterial effect, broad-spectrum and efficient bactericidal effect, excellent mechanical properties and good processing stability. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to specific embodiments, but it is not limited thereto.

[0025] Example 1 An antibacterial PVC sheet comprises the following raw materials in parts by weight: 100 parts polyvinyl chloride resin, 3 parts composite antibacterial agent, 3 parts toughening modifier, 2 parts stabilizer, 0.5 parts lubricant, 1 part processing aid, and 10 parts filler.

[0026] The preparation steps of the composite antibacterial agent are as follows: (1) Preparation of nano-Cu2O@mSiO2 core-shell particles: Weigh 5g of nano-cuprous oxide and add it to a three-necked flask containing 200mL of anhydrous ethanol and 50mL of deionized water. Disperse it by ultrasonication for 30 minutes to obtain a uniform suspension. Add 1g of CTAB and 2mL of 25% ammonia water to the suspension and stir at 400rpm and 40℃ for 30 minutes. Add 5mL of LTEOS dropwise using a constant pressure dropping funnel and continue stirring at 40℃ for 6 hours. After the reaction is completed, centrifuge at 8000rpm for 10 minutes, discard the supernatant, and wash the precipitate twice with anhydrous ethanol and deionized water. Place the washed precipitate in a vacuum drying oven at 60℃ and dry for 12 hours. Transfer it to a muffle furnace and heat it to 500℃ at a heating rate of 2℃ / min. Keep it at that temperature for 4 hours and cool it naturally to room temperature to obtain Cu2O@mSiO2 core-shell particles. (2) Chitosan quaternary ammonium salt loaded in mesoporous channels: Weigh 1g of chitosan quaternary ammonium salt, dissolve it in 100mL of deionized water, stir to dissolve, and prepare a 1wt% chitosan quaternary ammonium salt solution; add 5g of the prepared Cu2O@mSiO2 core-shell particles to the chitosan quaternary ammonium salt solution prepared above, place it in a vacuum drying oven, keep it for 30 minutes, then release the vacuum, and cycle the vacuum-decompression twice. Centrifuge the above impregnated mixture at 6000rpm for 10 minutes, collect the precipitate, wash the precipitate once with deionized water, centrifuge again, and place the precipitate in a vacuum drying oven at 50℃ for 24h to obtain composite particles; (3) Surface modification of silane coupling agent: 1g KH-550 was added to a flask containing 100ml anhydrous ethanol and 5ml deionized water, the pH was adjusted to 4-5, and the mixture was stirred to dissolve and obtain a modified solution; the composite particles prepared in step 2 were weighed and added to the above modified solution, ultrasonically dispersed for 5 minutes, and then magnetically stirred and refluxed in a 60℃ water bath for 4 hours. The mixture was centrifuged at 8000rpm for 8 minutes, the precipitate was washed twice with anhydrous ethanol, and then dried in a 60℃ vacuum drying oven for 12 hours. The dried product was then passed through a 200-mesh sieve to obtain a composite antibacterial agent.

[0027] The chitosan quaternary ammonium salt is hydroxypropyltrimethylammonium chloride chitosan.

[0028] The toughening modifier is an acrylonitrile-butadiene-styrene copolymer.

[0029] The stabilizer is a calcium-zinc composite stabilizer.

[0030] The lubricant is polyethylene wax.

[0031] The processing aid is a mixture of methyl methacrylate and butyl acrylate in a mass ratio of 7:3.

[0032] The filler is light calcium carbonate.

[0033] A method for preparing antibacterial PVC sheets includes the following steps: Weighing polyvinyl chloride resin, composite antibacterial agent, toughening modifier, stabilizer, lubricant, processing aid, and filler by weight; adding all weighed raw materials into a high-speed mixer and mixing at 300 rpm for 2 minutes; increasing the speed to 1000 rpm and mixing for 5 minutes; discharging the material into a cold mixer and cooling it to 40°C during mixing to obtain a dry mixture; feeding the cooled dry mixture into a conical twin-screw extruder, where it undergoes melt plasticization and technical conditioning to obtain a sheet blank; passing the extruded sheet blank sequentially through a sizing table and a cooling water tank for cooling and shaping, and then traction by a traction machine to cut it to the required length to obtain the antibacterial PVC sheet.

[0034] The extruder temperature settings for each section are as follows: barrel zone 1 160℃, zone 2 170℃, zone 3 175℃, confluence core 170℃, die head temperature 180℃, and screw speed 15 rpm.

[0035] Example 2 An antibacterial PVC sheet comprises the following raw materials in parts by weight: 110 parts of polyvinyl chloride resin, 9 parts of composite antibacterial agent, 9 parts of toughening modifier, 4 parts of stabilizer, 1 part of lubricant, 5 parts of processing aid, and 15 parts of filler.

[0036] The preparation steps of the composite antibacterial agent are as follows: (1) Preparation of nano-Cu2O@mSiO2 core-shell particles: Weigh 5g of nano-cuprous oxide and add it to a three-necked flask containing 200mL of anhydrous ethanol and 50mL of deionized water. Disperse it by ultrasonication for 30 minutes to obtain a uniform suspension. Add 1g of CTAB and 2mL of 25% ammonia water to the suspension and stir at 400rpm and 40℃ for 30 minutes. Add 5mL of LTEOS dropwise using a constant pressure dropping funnel and continue stirring at 40℃ for 6 hours. After the reaction is completed, centrifuge at 8000rpm for 10 minutes, discard the supernatant, and wash the precipitate twice with anhydrous ethanol and deionized water. Place the washed precipitate in a vacuum drying oven at 60℃ and dry for 12 hours. Transfer it to a muffle furnace and heat it to 500℃ at a heating rate of 2℃ / min. Keep it at that temperature for 4 hours and cool it naturally to room temperature to obtain Cu2O@mSiO2 core-shell particles. (2) Chitosan quaternary ammonium salt loaded in mesoporous channels: Weigh 1g of chitosan quaternary ammonium salt, dissolve it in 100mL of deionized water, stir to dissolve, and prepare a 1wt% chitosan quaternary ammonium salt solution; add 5g of the prepared Cu2O@mSiO2 core-shell particles to the chitosan quaternary ammonium salt solution prepared above, place it in a vacuum drying oven, keep it for 30 minutes, then release the vacuum, and cycle the vacuum-decompression twice. Centrifuge the above impregnated mixture at 6000rpm for 10 minutes, collect the precipitate, wash the precipitate once with deionized water, centrifuge again, and place the precipitate in a vacuum drying oven at 50℃ for 24h to obtain composite particles; (3) Surface modification of silane coupling agent: 1g KH-550 was added to a flask containing 100ml anhydrous ethanol and 5ml deionized water, the pH was adjusted to 4-5, and the mixture was stirred to dissolve and obtain a modified solution; the composite particles prepared in step 2 were weighed and added to the above modified solution, ultrasonically dispersed for 5 minutes, and then magnetically stirred and refluxed in a 60℃ water bath for 4 hours. The mixture was centrifuged at 8000rpm for 8 minutes, the precipitate was washed twice with anhydrous ethanol, and then dried in a 60℃ vacuum drying oven for 12 hours. The dried product was then passed through a 200-mesh sieve to obtain a composite antibacterial agent.

[0037] The chitosan quaternary ammonium salt is hydroxypropyltrimethylammonium chloride chitosan.

[0038] The toughening modifier is a methyl methacrylate-butadiene-styrene copolymer.

[0039] The stabilizer is a calcium-zinc composite stabilizer.

[0040] The lubricant is paraffin wax.

[0041] The processing aid is a mixture of methyl methacrylate and butyl acrylate in a mass ratio of 7:3.

[0042] The filler is light calcium carbonate.

[0043] A method for preparing antibacterial PVC sheets includes the following steps: Weighing polyvinyl chloride resin, composite antibacterial agent, toughening modifier, stabilizer, lubricant, processing aid, and filler by weight; adding all weighed raw materials into a high-speed mixer and mixing at 400 rpm for 3 minutes; increasing the speed to 1200 rpm and mixing for 7 minutes; discharging the material into a cold mixer and cooling it to 45°C during mixing to obtain a dry mixture; feeding the cooled dry mixture into a conical twin-screw extruder, where it undergoes melt plasticization and technical conditioning to obtain a sheet blank; passing the extruded sheet blank sequentially through a sizing table and a cooling water tank for cooling and shaping, and then traction by a traction machine to cut it to the required length to obtain the antibacterial PVC sheet.

[0044] The extruder temperature settings for each section are as follows: barrel zone 1 165℃, zone 2 175℃, zone 3 180℃, confluence core 172℃, die head temperature 188℃, and screw speed 25rpm.

[0045] Example 3 An antibacterial PVC sheet comprises the following raw materials in parts by weight: 120 parts of polyvinyl chloride resin, 15 parts of composite antibacterial agent, 15 parts of toughening modifier, 5 parts of stabilizer, 2 parts of lubricant, 8 parts of processing aid, and 20 parts of filler.

[0046] The preparation steps of the composite antibacterial agent are as follows: (1) Preparation of nano-Cu2O@mSiO2 core-shell particles: Weigh 5g of nano-cuprous oxide and add it to a three-necked flask containing 200mL of anhydrous ethanol and 50mL of deionized water. Disperse it by ultrasonication for 30 minutes to obtain a uniform suspension. Add 1g of CTAB and 2mL of 25% ammonia water to the suspension and stir at 400rpm and 40℃ for 30 minutes. Add 5mL of LTEOS dropwise using a constant pressure dropping funnel and continue stirring at 40℃ for 6 hours. After the reaction is completed, centrifuge at 8000rpm for 10 minutes, discard the supernatant, and wash the precipitate twice with anhydrous ethanol and deionized water. Place the washed precipitate in a vacuum drying oven at 60℃ and dry for 12 hours. Transfer it to a muffle furnace and heat it to 500℃ at a heating rate of 2℃ / min. Keep it at that temperature for 4 hours and cool it naturally to room temperature to obtain Cu2O@mSiO2 core-shell particles. (2) Chitosan quaternary ammonium salt loaded in mesoporous channels: Weigh 1g of chitosan quaternary ammonium salt, dissolve it in 100mL of deionized water, stir to dissolve, and prepare a 1wt% chitosan quaternary ammonium salt solution; add 5g of the prepared Cu2O@mSiO2 core-shell particles to the chitosan quaternary ammonium salt solution prepared above, place it in a vacuum drying oven, keep it for 30 minutes, then release the vacuum, and cycle the vacuum-decompression twice. Centrifuge the above impregnated mixture at 6000rpm for 10 minutes, collect the precipitate, wash the precipitate once with deionized water, centrifuge again, and place the precipitate in a vacuum drying oven at 50℃ for 24h to obtain composite particles; (3) Surface modification of silane coupling agent: 1g KH-550 was added to a flask containing 100ml anhydrous ethanol and 5ml deionized water, the pH was adjusted to 4-5, and the mixture was stirred to dissolve and obtain a modified solution; the composite particles prepared in step 2 were weighed and added to the above modified solution, ultrasonically dispersed for 5 minutes, and then magnetically stirred and refluxed in a 60℃ water bath for 4 hours. The mixture was centrifuged at 8000rpm for 8 minutes, the precipitate was washed twice with anhydrous ethanol, and then dried in a 60℃ vacuum drying oven for 12 hours. The dried product was then passed through a 200-mesh sieve to obtain a composite antibacterial agent.

[0047] The chitosan quaternary ammonium salt is hydroxypropyltrimethylammonium chloride chitosan.

[0048] The toughening modifier is chlorinated polyethylene.

[0049] The stabilizer is a calcium-zinc composite stabilizer.

[0050] The lubricant is stearic acid.

[0051] The processing aid is a mixture of methyl methacrylate and butyl acrylate in a mass ratio of 7:3.

[0052] The filler is light calcium carbonate.

[0053] A method for preparing antibacterial PVC sheets includes the following steps: Weighing polyvinyl chloride resin, composite antibacterial agent, toughening modifier, stabilizer, lubricant, processing aid, and filler by weight; adding all weighed raw materials into a high-speed mixer and mixing at 500 rpm for 3 minutes; increasing the speed to 1500 rpm and mixing for 10 minutes; discharging the material into a cold mixer and cooling it to 50°C during mixing to obtain a dry mixture; feeding the cooled dry mixture into a conical twin-screw extruder, where it undergoes melt plasticization and technical sizing to obtain a sheet blank; passing the extruded sheet blank sequentially through a sizing table and a cooling water tank for cooling and sizing, and then traction by a traction machine to cut it to the required length to obtain the antibacterial PVC sheet.

[0054] The extruder temperature settings for each section are as follows: barrel zone 1 170℃, zone 2 180℃, zone 3 185℃, confluence core 175℃, die head temperature 195℃, and screw speed 30rpm.

[0055] Comparative Example 1 Compared with Example 3, this comparative example is identical to Example 3 except that no compound antibacterial agent is added. All other raw materials and steps are the same as in Example 3.

[0056] Comparative Example 2 Compared with Example 3, this comparative example differs from Example 3 in that, except for the preparation of nano-Cu2O@mSiO2 core-shell particles and chitosan quaternary ammonium salt mixed at a mass ratio of 5:1 in the composite antibacterial agent, and the surface modification of nano-Cu2O@mSiO2 core-shell particles with silane coupling agent, all other raw materials and steps are the same as in Example 3.

[0057] Comparative Example 3 Compared with Example 3, this comparative example differs from Example 3 except that the prepared nano-Cu2O@mSiO2 core-shell particles and chitosan quaternary ammonium salt are mixed in a mass ratio of 5:1 in the composite antibacterial agent, and the nano-Cu2O@mSiO2 core-shell particles are not modified with silane coupling agent. All other raw materials and steps are the same as in Example 3.

[0058] Performance testing The antibacterial PVC sheets prepared in the examples and comparative examples were tested for their Escherichia coli inhibition rate according to GB / T31402-2023 "Determination of antibacterial activity of plastics and other non-porous materials". Then, after standing at room temperature for 200 days according to QB / T2591 "Antibacterial Plastics—Test Methods for Antibacterial Properties and Antibacterial Effects", the Escherichia coli inhibition rate was tested again, and the retention rate was calculated. The tensile strength of the PVC sheets in each treatment group was determined according to GB / T 1040.2-2022 "Determination of Tensile Properties of Plastics Part 2: Test Conditions for Molded and Extruded Plastics". The notched impact strength of the PVC sheets prepared in each treatment group was tested according to GB / T1843-2008 "Plastics Cantilever Beam Impact Test Method". The above test data are shown in Table 1.

[0059] Table 1. Performance test results of PVC sheets in each treatment group As shown in Table 1, the antibacterial rate of the PVC sheets prepared in Examples 1-3 of this invention is as high as 98% or more. Among them, the PVC sheet of Example 3 has the strongest and most durable antibacterial properties, and the PVC sheets prepared in the examples have excellent mechanical properties. In contrast, Comparative Example 1, which does not add the composite antibacterial agent, has no other antibacterial components and its antibacterial rate is almost non-existent. In Comparative Example 2, the components of the composite antibacterial agent are physically mixed without vacuum loading. Its free chitosan quaternary ammonium salt is easily thermally decomposed during high-temperature processing and has no mesoporous protection. It is easy to migrate and be lost during long-term storage or use, so the antibacterial retention rate is significantly reduced. In terms of mechanics, after modification with KH-550, the core-shell particles have good compatibility with the PVC matrix and are evenly dispersed. Therefore, the tensile strength is close to that of Example 3. However, the free chitosan quaternary ammonium salt, as an organic small molecule, will interfere with the interfacial bonding, resulting in a slight decrease in impact strength. Comparative Example 3, modified with KH-550, exhibited severe aggregation within the hydrophobic PVC matrix due to the hydrophilic and oleophobic surface of the modified core-shell particles. A large number of antibacterial particles were embedded within these aggregates, unable to contact the bacterial surface, resulting in a significant reduction in the initial antibacterial rate. Simultaneously, the free chitosan quaternary ammonium salt still suffered from thermal decomposition and loss, and the cuprous oxide release was also hampered by aggregation, leading to a decrease in the long-term antibacterial rate retention. Furthermore, the severe aggregation of the quinary particles in Comparative Example 3 created significant stress concentration points, making it prone to cracking during tension and segmentation during impact. Additionally, the unmodified hydrophilic surface adsorbed small amounts of water and low-molecular-weight substances, further deteriorating the integrity of the PVC matrix. Consequently, both tensile strength and notched impact strength were significantly degraded, with a marked decrease in impact strength.

[0060] It should be noted that the above embodiments are merely some preferred embodiments of the present invention, and not all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

Claims

1. An antibacterial PVC board, characterized in that, The raw materials include the following parts by weight: 100-120 parts of polyvinyl chloride resin, 3-15 parts of composite antibacterial agent, 3-15 parts of toughening modifier, 2-5 parts of stabilizer, 0.5-2 parts of lubricant, 1-8 parts of processing aid, and 10-20 parts of filler.

2. The antibacterial PVC board according to claim 1, characterized in that, The preparation steps of the composite antibacterial agent are as follows: (1) Preparation of nano-Cu2O@mSiO2 core-shell particles: Weigh 5g of nano-cuprous oxide and add it to a three-necked flask containing 200mL of anhydrous ethanol and 50mL of deionized water. Disperse it by ultrasonication for 30 minutes to obtain a uniform suspension. Add 1g of CTAB and 2mL of 25% ammonia water to the suspension and stir at 400rpm and 40℃ for 30 minutes. Add 5mL of LTEOS dropwise using a constant pressure dropping funnel and continue stirring at 40℃ for 6 hours. After the reaction is completed, centrifuge at 8000rpm for 10 minutes, discard the supernatant, and wash the precipitate twice with anhydrous ethanol and deionized water. Place the washed precipitate in a vacuum drying oven at 60℃ and dry for 12 hours. Transfer it to a muffle furnace and heat it to 500℃ at a heating rate of 2℃ / min. Keep it at that temperature for 4 hours and cool it naturally to room temperature to obtain Cu2O@mSiO2 core-shell particles. (2) Chitosan quaternary ammonium salt loaded in mesoporous channels: First, weigh 1g of chitosan quaternary ammonium salt, dissolve it in 100mL of deionized water, stir to dissolve, and prepare a 1wt% chitosan quaternary ammonium salt solution; add 5g of the prepared Cu2O@mSiO2 core-shell particles to the chitosan quaternary ammonium salt solution prepared above, place it in a vacuum drying oven, keep it for 30 minutes, then release the vacuum, and cycle the vacuum-decompression twice. Centrifuge the above impregnated mixture at 6000rpm for 10 minutes, collect the precipitate, wash the precipitate once with deionized water, centrifuge again, and place the precipitate in a vacuum drying oven at 50℃ for 24h to obtain composite particles; (3) Surface modification of silane coupling agent: 1g KH-550 was added to a flask containing 100ml anhydrous ethanol and 5ml deionized water, the pH was adjusted to 4-5, and the mixture was stirred to dissolve and obtain a modified solution; the composite particles prepared in step 2 were weighed and added to the above modified solution, ultrasonically dispersed for 5 minutes, and then magnetically stirred and refluxed in a 60℃ water bath for 4 hours. The mixture was centrifuged at 8000rpm for 8 minutes, the precipitate was washed twice with anhydrous ethanol, and then dried in a 60℃ vacuum drying oven for 12 hours. The dried product was then passed through a 200-mesh sieve to obtain a composite antibacterial agent.

3. The antibacterial PVC board according to claim 2, characterized in that, The chitosan quaternary ammonium salt is hydroxypropyltrimethylammonium chloride chitosan.

4. The antibacterial PVC board according to claim 1, characterized in that, The toughening modifier is one of chlorinated polyethylene, acrylonitrile-butadiene-styrene copolymer, and methyl methacrylate-butadiene-styrene copolymer.

5. The antibacterial PVC sheet according to claim 1, characterized in that, The stabilizer is a calcium-zinc composite stabilizer.

6. The antibacterial PVC sheet according to claim 1, characterized in that, The lubricant is one of stearic acid, polyethylene wax, or paraffin wax.

7. The antibacterial PVC sheet according to claim 1, characterized in that, The processing aid is a mixture of methyl methacrylate and butyl acrylate in a mass ratio of 7:

3.

8. The antibacterial PVC sheet according to claim 1, characterized in that, The filler is light calcium carbonate.

9. A method for preparing an antibacterial PVC sheet according to any one of claims 1-8, characterized in that, The preparation process includes the following steps: Weigh polyvinyl chloride resin, composite antibacterial agent, toughening modifier, stabilizer, lubricant, processing aid, and filler according to weight parts. Put all the weighed raw materials into a high-speed mixer and mix at 300-500 rpm for 2-3 minutes. Increase the speed to 1000-1500 rpm and mix for 5-10 minutes. Discharge the material into a cold mixer and cool it to 40-50℃ while stirring to obtain a dry mixture. Send the cooled dry mixture into a conical twin-screw extruder, where it is melt-plasticized and technically shaped to obtain a sheet blank. Pass the extruded sheet blank through a sizing table and a cooling water tank for cooling and shaping. Then, traction machine cuts it to the required length to obtain antibacterial PVC sheets.

10. The method for preparing antibacterial PVC sheets according to claim 9, characterized in that, The extruder temperature settings for each section are as follows: barrel zone 1 160-170℃, zone 2 170-180℃, zone 3 175-185℃, confluence core 170-175℃, die head temperature 180-195℃, and screw speed 15-30 rpm.

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